Abstract:

Method and device for therapeutic or aesthetic treatment of the skin
performs a combination of dermabrasion to mechanically modify at least an
outer layer of the skin in a first region and phototherapy. The device
preferably employs a skin interface element with projections protruding
from a substrate which is moved in a vibratory motion by a vibration
generating mechanism. This is combined with an illumination system
deployed to direct a therapeutically relevant dosage of light towards a
surface of the skin against which the skin interface unit is in contact.

Claims:

1. A method for treatment of the skin comprising implementing a combined
treatment including substantially contemporaneous or sequential steps
of:(a) performing dermabrasion to mechanically modify at least an outer
layer of the skin in a first region; and(b) delivering to said first
region a therapeutically relevant dosage of light so as to perform
phototherapy.

2. The method of claim 1, wherein said dermabrasion is performed prior to
or during said delivering in such a manner as to reduce obstruction of
the light passing through the outer layer of the skin.

3. The method of claim 1, wherein said dermabrasion is micro-dermabrasion.

4. The method of claim 1, wherein said dermabrasion is performed by
bringing a plurality of micro-protrusions into contact with the skin and
generating vibratory motion of the micro-protrusions.

5. The method of claim 4, wherein said micro-protrusions are provided with
an antibacterial coating.

6. The method of claim 4, wherein at least part of a support structure
supporting said micro-protrusions is formed from a material substantially
transparent to said light, and wherein at least some of said light is
delivered via said substantially transparent material.

7. The method of claim 1, further comprising, during said dermabrasion,
delivering to said first region of skin a therapeutic substance.

8. The method of claim 7, wherein said therapeutic substance is an agent
for enhancing action of said phototherapy.

9. A device for treatment of the skin comprising:(a) a skin interface
element including a substrate provided with a plurality of
protrusions;(b) a vibration generating mechanism mechanically linked to
said skin interface element so as to generate vibratory motion of said
skin interface element; and(c) an illumination system deployed to direct
a therapeutically relevant dosage of light towards a surface of the skin
against which said skin interface unit is in contact.

10. The device of claim 9, further comprising a housing and a support
structure supporting said skin interface element relative to said
housing, wherein at least part of at least one of said substrate and said
support structure is formed from a material substantially transparent to
said light, said illumination system being deployed to direct at least
some of said light via said substantially transparent material.

11. The device of claim 9, wherein said protrusions project to a height
above said substrate of no greater than 200 microns;

12. The device of claim 9, wherein said protrusions project to a height
above said substrate of between about 20 microns and about 100 microns.

13. The device of claim 9, wherein said protrusions are arranged in a
two-dimensional array.

14. The device of claim 9, wherein said protrusions have a shape selected
from the group comprising: pyramids, cones and rods.

15. The device of claim 9, wherein said protrusions are integrally formed
with said substrate.

16. The device of claim 9, wherein said protrusions and said substrate are
formed from a single crystal of material.

17. The device of claim 9, wherein said protrusions and said substrate are
formed from a unitary block of material processed primarily by wet
etching techniques.

18. The device of claim 9, wherein said protrusions are formed from a
material selected from the group consisting of: silicon, a polymer, a
metal, a metal alloy, and a ceramic material.

19. The device of claim 9, wherein said protrusions are provided with an
antibacterial coating.

20. The device of claim 9, wherein said vibration generating mechanism
includes a motor configured for rotating an eccentric weight about an
axis.

21. The device of claim 9, wherein said vibration generating mechanism is
configured to generate vibratory motion corresponding to an orbital
motion in a plane of said substrate.

22. The device of claim 9, wherein said vibration generating mechanism is
configured to generate vibratory motion having a non-zero component
perpendicular to a plane of said substrate.

23. The device of claim 9, wherein said vibration generating mechanism is
configured to generate vibratory motion having a frequency in the range
between 50 Hz and 200 Hz.

24. The device of claim 9, wherein said vibration generating mechanism is
configured to generate vibratory motion having a frequency in the range
of 140 Hz.+-.25 Hz.

25. The device of claim 9, further comprising a pressure-limiting switch
arrangement associated with said skin interface element and responsive to
contact pressure of said skin interface element above a given limit to
interrupt operation of said vibration generating mechanism.

26. The device of claim 9, further comprising a housing, wherein said skin
interface element is resiliently mounted relative to said housing, and
wherein said vibration generating mechanism is mechanically linked to
said skin interface element so as to generate vibratory motion of said
skin interface element relative to said housing.

27. The device of claim 9, further comprising a housing mechanically
supporting said skin interface element, said vibration generating
mechanism, said illumination system and at least one electric battery,
wherein said vibration generating mechanism and said illumination system
are powered exclusively by said at least one electric battery.

28. A device for treatment of the skin comprising:(a) a skin interface
element including a substrate provided with a plurality of protrusions;
and(b) an antibacterial coating applied at least to surfaces of said
protrusions.

29. The device of claim 28, wherein said antibacterial coating is applied
to a surface of said substrate.

30. The device of claim 28, wherein said plurality of projections are
implemented as a plurality of hollow microneedles.

31. The device of claim 28, wherein said antibacterial coating includes
titanium dioxide.

32. The device of claim 28, wherein said antibacterial coating includes
metal ions of at least one metal selected from the group consisting of:
silver, zinc, cobalt, aluminum, mercury and copper.

33. The device of claim 28, wherein said antibacterial coating includes
benzalkonium chloride.

Description:

[0002]Conventional micro-dermabrasion abrades the skin with a
high-pressure flow of crystals. Micro-dermabrasion was developed in Italy
in 1985; its use was widespread in European countries prior to its
introduction and popularity in the United States. This technology offers
the advantages of low risk and rapid recovery compared with more
traditional resurfacing modalities such as laser and can be effective in
the appropriate patient population. Abrading the superficial layers of
the skin induces cellular proliferation and production of various
elements of the extracellular matrix, resulting in an improved aesthetic
appearance of the skin. Providing this process is contained to the
epidermis and shallow dermis, scarring is unlikely. Additional modalities
for dermal abrasion include traditional dermabrasion, chemical peeling,
laser resurfacing. All of these resurfacing procedures exert their
effects through different degrees of epidermal and dermal ablation. The
results and the indications for each modality depend on the depth of
ablation. These modalities are invariably painful and provide significant
local side effects such as erythema, edema, itching, burning sensation,
sun sensitivity and the like.

[0003]Photomodulation refers to the use of low energy, narrow-band light
with or without a specific pulse (on/off) sequence. Photomodulation has
been shown to regulate cell activity. This process is relatively new and
differs from conventional methods in that it is non-thermal. Light
emitting diode (LED) light sources are frequently used for
photomodulation, which has been shown to improve photoaging skin changes,
facial texture, fine lines, background erythema, pigmentation and wound
healing. Photomodulation is thought to be produced, among others, by the
activation (and increased energy levels) of light-sensitive organelles
(sensors) present in skin cells and by the generation of ROS (Reactive
Oxygen Species). The effects of photomodulation can be further enhanced
by introducing substances (e.g., creams) that become active when exposed
to light into the treated area (photodynamic therapy). In certain
specific indications such as acne, phototherapy can be performed by
projecting blue light, which is phototoxic to the acne bacteria.

[0004]Other modes of phototherapy for treatment of the skin employ higher
energy radiation, usually in the infrared part of the spectrum, for
delivering heat to selected layers of the skin. Common examples include
the use of CO2 lasers (wavelength about 10,000 nm) or Er:YAG lasers
(wavelength about 3,000 nm) for peeling or skin resurfacing in the
epidermis or a portion thereof, and the use of Nd:YAG lasers (wavelength
of about 1,000-1,500 nm) which is less absorbed by superficial layers of
the skin and penetrates deeper, performing applications such as tattoo
removal, hair removal, acne treatment etc.

[0005]In any and all of the aforementioned modes of phototherapy where the
target layer of tissue is not the most superficial layer of the skin,
energy losses occur to varying degrees through absorption, scattering or
reflection of radiation by the higher layers, thereby reducing the
efficacy of the process.

[0006]There is therefore a need for a method and device which would employ
a combination of dermabrasion and phototherapy to advantage, optionally
with delivery of additional therapeutic substances. It would also be
advantageous to improve the efficacy of a phototherapy treatment by
employing dermabrasion to reduce the barrier effect of at least one outer
layer of the skin to penetration of the corresponding radiation.

SUMMARY OF THE INVENTION

[0007]The present invention is a method and device for performing a
combination of dermabrasion and phototherapy.

[0008]According to the teachings of the present invention there is
provided, a method for treatment of the skin comprising implementing a
combined treatment including substantially contemporaneous or sequential
steps of: (a) performing dermabrasion to mechanically modify at least an
outer layer of the skin in a first region; and (b) delivering to the
first region a therapeutically relevant dosage of light so as to perform
phototherapy.

[0009]According to a further feature of the present invention, the
dermabrasion is performed prior to or during the delivering in such a
manner as to reduce obstruction of the light passing through the outer
layer of the skin.

[0010]According to a further feature of the present invention, the
dermabrasion is micro-dermabrasion.

[0011]According to a further feature of the present invention, the
dermabrasion is performed by bringing a plurality of micro-protrusions
into contact with the skin and generating vibratory motion of the
micro-protrusions.

[0012]According to a further feature of the present invention, the
micro-protrusions are provided with an antibacterial coating.

[0013]According to a further feature of the present invention, at least
part of a support structure supporting the micro-protrusions is formed
from a material substantially transparent to the light, and wherein at
least some of the light is delivered via the substantially transparent
material.

[0014]According to a further feature of the present invention, during the
dermabrasion, a therapeutic substance is delivered to the first region of
skin.

[0015]According to a further feature of the present invention, the
therapeutic substance is an agent for enhancing action of the
phototherapy.

[0016]There is also provided according to the teachings of the present
invention, a device for treatment of the skin comprising: (a) a skin
interface element including a substrate provided with a plurality of
protrusions; (b) a vibration generating mechanism mechanically linked to
the skin interface element so as to generate vibratory motion of the skin
interface element; and (c) an illumination system deployed to direct a
therapeutically relevant dosage of light towards a surface of the skin
against which the skin interface unit is in contact.

[0017]According to a further feature of the present invention, there is
also provided a housing and a support structure supporting the skin
interface element relative to the housing, wherein at least part of at
least one of the substrate and the support structure is formed from a
material substantially transparent to the light, the illumination system
being deployed to direct at least some of the light via the substantially
transparent material.

[0018]According to a further feature of the present invention, the
protrusions project to a height above the substrate of no greater than
200 microns, and preferably between about 20 microns and about 100
microns.

[0019]According to a further feature of the present invention, the
protrusions are arranged in a two-dimensional array.

[0020]According to a further feature of the present invention, the
protrusions have a shape selected from the group comprising: pyramids,
cones and rods.

[0021]According to a further feature of the present invention, the
protrusions are integrally formed with the substrate.

[0022]According to a further feature of the present invention, the
protrusions and the substrate are formed from a single crystal of
material.

[0023]According to a further feature of the present invention, the
protrusions and the substrate are formed from a unitary block of material
processed primarily by wet etching techniques.

[0024]According to a further feature of the present invention, the
protrusions are formed from a material selected from the group consisting
of: silicon, a polymer, a metal, a metal alloy, and a ceramic material.

[0025]According to a further feature of the present invention, the
protrusions are provided with an antibacterial coating.

[0026]According to a further feature of the present invention, the
vibration generating mechanism includes a motor configured for rotating
an eccentric weight about an axis.

[0027]According to a further feature of the present invention, the
vibration generating mechanism is configured to generate vibratory motion
corresponding to an orbital motion in a plane of the substrate.

[0028]According to a further feature of the present invention, the
vibration generating mechanism is configured to generate vibratory motion
having a non-zero component perpendicular to a plane of the substrate.

[0029]According to a further feature of the present invention, the
vibration generating mechanism is configured to generate vibratory motion
having a frequency in the range between 50 Hz and 200 Hz.

[0030]According to a further feature of the present invention, the
vibration generating mechanism is configured to generate vibratory motion
having a frequency in the range of 140 Hz±25 Hz.

[0031]According to a further feature of the present invention, there is
also provided a pressure-limiting switch arrangement associated with the
skin interface element and responsive to contact pressure of the skin
interface element above a given limit to interrupt operation of the
vibration generating mechanism.

[0032]According to a further feature of the present invention, there is
also provided a housing, wherein the skin interface element is
resiliently mounted relative to the housing, and wherein the vibration
generating mechanism is mechanically linked to the skin interface element
so as to generate vibratory motion of the skin interface element relative
to the housing.

[0033]According to a further feature of the present invention, there is
also provided a housing mechanically supporting the skin interface
element, the vibration generating mechanism, the illumination system and
at least one electric battery, wherein the vibration generating mechanism
and the illumination system are powered exclusively by the at least one
electric battery.

[0034]There is also provided according to the teachings of the present
invention, a device for treatment of the skin comprising: (a) a skin
interface element including a substrate provided with a plurality of
protrusions; and (b) an antibacterial coating applied at least to
surfaces of the protrusions.

[0035]According to a further feature of the present invention, the
antibacterial coating is applied to a surface of the substrate.

[0036]According to a further feature of the present invention, the
plurality of projections are implemented as a plurality of hollow
microneedles.

[0037]According to a further feature of the present invention, the
antibacterial coating includes titanium dioxide.

[0038]According to a further feature of the present invention, the
antibacterial coating includes metal ions of at least one metal selected
from the group consisting of: silver, zinc, cobalt, aluminum, mercury and
copper.

[0039]According to a further feature of the present invention, the
antibacterial coating includes benzalkonium chloride.

BRIEF DESCRIPTION OF THE DRAWINGS

[0040]The invention is herein described, by way of example only, with
reference to the accompanying drawings, wherein:

[0041]FIG. 1 is a schematic representation of a device for combined
dermabrasion and phototherapy of the skin, constructed and operative
according to the teachings of the present invention;

[0042]FIG. 2 is a schematic representation of a variant of the device of
FIG. 1 illustrating an additional pressure-limiting switch arrangement;

[0043]FIG. 3 is an isometric view of a first implementation of a skin
interface element from the device of FIG. 1;

[0044]FIG. 3A is an enlarged view of a single micro-protrusion from the
skin interface element of FIG. 3;

[0045]FIG. 4 is an isometric view of a second implementation of a skin
interface element from the device of FIG. 1;

[0046]FIG. 4A is an enlarged view of a single micro-protrusion from the
skin interface element of FIG. 4;

[0047]FIG. 5 is an isometric view of an implementation of the device of
FIG. 1;

[0048]FIG. 6 is an enlarged view of a part of FIG. 5 showing a skin
interface element;

[0049]FIG. 7 is an enlarged view of a small region of FIG. 6 showing the
structure of the protrusions; and

[0050]FIG. 8 is a partially cut-away isometric view of a part of the
device of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051]The present invention is a method and device combining dermabrasion
with phototherapy.

[0052]The principles and operation of methods and devices according to the
present invention may be better understood with reference to the drawings
and the accompanying description.

[0053]Before turning to specific examples of preferred devices according
to the present invention, it should be appreciated that the invention is
applicable generally to any and all combined techniques in which
dermabrasion and phototherapy are performed substantially
contemporaneously or sequentially in such a manner that they provide
additive or synergistic therapeutic or aesthetic results.

[0054]Thus, in general terms, the present invention provides a method for
treatment of the skin implementing a combined treatment including
substantially contemporaneous or sequential steps of: (a) performing
dermabrasion to mechanically modify at least an outer layer of the skin
in a first region; and (b) delivering to the first region a
therapeutically relevant dosage of light so as to perform phototherapy.
According to one particularly significant subset of applications, the
dermabrasion is performed prior to or during the delivering of light in
such a manner as to reduce obstruction of the light passing through the
outer layer of the skin, thereby improving efficacy of the phototherapy.
Additionally, or alternatively, a therapeutic substance is delivered to
the first region of skin during the dermabrasion. The therapeutic
substance may be a medication for performing a complementary or
independent therapeutic function, and according to one particularly
preferred example, may be an agent for enhancing action of the
phototherapy or whose action is actuated or enhanced by the light
administered during the phototherapy.

[0055]According to most preferred implementations, the dermabrasion, which
is preferably implemented as micro-dermabrasion, is performed by bringing
a plurality of micro-protrusions into contact with the skin and
generating vibratory motion of the micro-protrusions. The use of
microprotrusions has also been found to give rise to localized heating of
the skin near the microprotrusions' tips. This heating is also believed
to contribute to tissue regeneration, providing a further synergistic
effect. Various features of preferred devices for performing both
dermabrasion and phototherapy will be described in detail below.

[0056]Referring now to the device of the present invention, FIG. 1
illustrates schematically a device, generally designated 100, constructed
and operative according to the teachings of the present invention, for
therapeutic treatment of the skin. Generally speaking, device 100
includes a skin interface element 102 having a substrate 104 from which
project a plurality of protrusions 106. A vibration generating mechanism
108 is mechanically linked to skin interface element 102 so as to
generate vibratory motion of skin interface element 102. An illumination
system 109 is deployed to direct a therapeutically relevant dosage of
light towards a surface of the skin against which the skin interface unit
is in contact.

[0057]The combination of the vibratory motion together with the
protrusions 106 achieves superficial abrasion of the outer surface of the
skin, typically only at the level of the stratum corneum (SC) or, in
relevant specific cases, the epidermis, and is thus effective for a wide
range of cosmetic and medical applications as are known for
micro-dermabrasion or dermabrasion. This dermabrasion in combination with
phototherapy performed by illumination system 109 provides an additive
and/or synergistic therapeutic or aesthetic effect, as will be described.
These and other advantages of the present invention will become clearer
from the following description.

[0058]Before addressing the features of the present invention in more
detail, it will be helpful to define certain terminology as used herein
in the description and claims. Firstly, reference is made to "vibration"
and "vibratory motion". These terms are used herein in the description
and claims to refer to any repetitive oscillatory motion about a mean
position in one or more dimension. These vibrations may be linear (i.e.,
one dimensional) or orbital (i.e., circular or elliptical), or may have a
more complex form such as results from, for example, differing vibration
frequencies in two perpendicular directions. The vibratory motion is
preferably translational rather than rotating. In other words, the motion
of all parts of skin interface element 102 is preferably roughly the same
so that the entire element vibrates to-and-fro, or orbits, without
overall rotation of skin interface element 102.

[0059]Typically, the vibrations are actually oscillating forces applied to
the skin interface element 102 and the amplitude of the vibrations
varies, depending upon the damping effect of engagement with the skin.

[0060]The term "superficial" is used herein in the description and claims
to refer to abrasion of the skin which does not extend to a depth of more
than 200 microns. For cosmetic applications, the superficial abrasion is
preferably kept to a depth less than 100 microns, thereby avoiding fully
breaching the upper barrier layers of the skin (stratum corneum and upper
epidermal layers), so as to minimize pain, damage to the viable dermis,
and other adverse effects. For certain particularly preferred
applications, an abrasion depth of roughly 10-20 microns may be preferred
in order to breach the stratum corneum (SC) alone without damaging living
cells. For this purpose, penetration into the layers of the skin is
preferably limited to less than 100 microns, and most preferably less
than about 70 microns. The actual height of the protrusions 106 above the
surface of substrate 104 may be somewhat larger than the desired
penetration depth, since the entire height does not typically penetrate.
Preferred heights for protrusions 106 are thus typically in the range of
about 20 microns to about 100 microns, and most preferably 60
microns±20 microns. For medical applications, on the other hand,
penetration depths in excess of 100 microns are typically indicated. In
this case, protrusions of height in the range of 100 microns up to 200
microns are typically used, although taller protrusions up to about 500
microns could also be useful in certain applications.

[0061]The term "dermabrasion" is used herein generically to refer to any
and all techniques in which skin is mechanically abraded, independent of
depth. The term thus defined includes the special case of
"micro-dermabrasion" in which the abrasion is performed to a depth of no
more than 200 microns.

[0062]The term "protrusions" is used to refer to any repetitive structure
of projecting features which project from the surface of substrate 104.
The protrusions may be any shape, pointed or blunt-ended, rounded in
cross-section or with lateral cutting edges, hollow or solid. Non
limiting examples of particularly preferred forms of protrusion include:
symmetrical or asymmetric pyramids of polygonal base, pointed or
truncated cones, and cylindrical or polygonal rods. The protrusions of
the present invention are referred to interchangeably as
"micro-protrusions" in view of their preferred ranges of dimensions under
500 microns as described above.

[0063]The term "phototherapy" is used herein as a generic term to refer to
any and all processes in which visible or invisible (IR or UV) light is
used for therapeutic or aesthetic purposes on the skin or any other
surface of a human or animal body. Phototherapy thus defined encompasses
a wide range of different light-based techniques including, but not
limited to, photomodulation, photodynamic therapy (PDT) and
photoablation.

[0064]The phrase "therapeutically relevant" is used herein in the
description and claims referring to application of light to denote a
process which, under the conditions employed, produces or causes a change
in the tissue to which it is applied. The change may be conditional upon
the presence of additional substances (e.g., a photo-sensitizer) and may
not be readily or immediately discernable. The phrase "therapeutically
relevant" is used to distinguish the present invention from illumination
arrangements which are designed and employed only for improving
visibility or as part of an imaging system.

[0065]Finally with regard to terminology, to specify the temporal relation
between the dermabrasion and phototherapy of the present invention, these
processes are described as being performed "substantially
contemporaneously" or "sequentially". The phrase "substantially
contemporaneously" is used herein to refer to processes being performed
with some degree of temporal overlap. This includes possibilities of both
processes being performed simultaneously, of one being performed during a
time slot within the duration of the other, and of a later process
starting during the duration of the former process and continuing after
the former process has stopped. The term "sequentially" is used herein to
refer to two processes which are performed without temporal overlap, but
within a sufficiently short time period of each other that the effect of
the earlier process is still present in order for the later process to be
additive or synergistic in its effects.

[0066]Turning now to the features of the present invention in more detail,
protrusions 106 are preferably arranged in a two-dimensional array, and
typically in a rectangular array, i.e., with protrusions spaces along two
perpendicular directions. The area covered by the array is not
necessarily, or even typically, rectangular, and roughly round or
octagonal areas may have advantages in terms of symmetry of coverage and
accessibility to hard-to-reach regions of the skin.

[0067]Two non-limiting examples of arrangements of protrusions are
illustrated in FIGS. 3 and 4. Most preferably, dimensions of the
two-dimensional array are at least 8×8, and more preferably at
least 10×10, corresponding to a total of at least 100 protrusions.
Typically, several hundred protrusions are provided on an area of less
than one square centimeter. In the examples illustrated here, FIG. 3
(enlarged in FIG. 3A) shows octagonal pyramid protrusions, while FIG. 4
(enlarged in FIG. 4A) shows square pyramidal protrusions. In either case,
the protrusions may optionally be modified by truncation to form a
stronger but less sharp form.

[0068]Protrusions 106 may be produced using a wide range of different
technologies from a wide variety of different materials. For example,
MEMS technology (using wet or dry etching or a combination of the two)
may be employed to process a unitary block of silicon (single crystal) or
other etchable material to produce the protrusions-plus-substrate
structure. Suitable MEMS techniques for forming a wide variety of
conical, pyramidal and cylindrical protrusions projecting from a
substrate are well known in the art, for example, in the context of
microneedle technology. Most preferably, low cost MEMS techniques based
primarily on wet etching techniques are used.

[0069]Other technologies suitable for forming the skin interface element
include injection or micro-injection molding, hot embossing and machining
techniques which be used to produce the skin interface element from
various polymers or other moldable materials. According to a further
option, foils (such as steel, titanium, or other metals or metal alloys)
may be processed by cutting (wire cutting, laser cutting, punching or
other cutting processes), with or without post cutting processing, to
form protrusions 106. Ceramics may also be used. In most preferred
implementations, protrusions 106 are integrally formed with substrate
104.

[0070]Referring again to FIG. 1, skin interface element 102 is preferably
supported relative to a housing 110 via a resilient support 112 which
allows vibratory motion of skin interface element 102 without excessive
damping from the mass of housing 110 and the user's hand holding the
device. The isolation of most of the vibrational energy from the main
body of housing 110 also serves to improve user comfort and renders the
device more energy efficient. In the case of FIG. 1, resilient support
112 is shown as a flexible membrane which performs an additional function
of sealing between skin interface element 102 and housing 110 to prevent
ingress of dirt and other foreign matter. Resilient support 112 may be
formed of any suitable resilient material, including but not limited to,
natural or artificial rubber or silicone.

[0071]Generation of vibration can be achieved using any of a wide range of
mechanisms. By way of one preferred but non-limiting example, vibration
generating mechanism 108 as illustrated here includes an electric motor
114 driving an eccentric weight 116 about an axis 118. The motor is
driven by a power supply 120, typically implemented as one or more
battery mounted within housing 110, and is controlled by on/off switch
122. Vibration generating mechanism 108 can thus be implemented cheaply
using compact off-the-shelf components such as those employed for
vibrating notification in cellular telephones. Alternatively the
vibration generating mechanism can be implemented as a piezoelectric
crystal or a solenoid.

[0072]Although on/off switch 122 is illustrated here as a simple on/off
push-button switch, it should be noted that alternative electrical switch
arrangements and/or electronic control circuitry may be used to advantage
to provide various modes of control over the device. By way of
non-limiting examples, modes of actuation may include one or more of the
following: [0073]Bistable on/off switch (slider or push-button)
manually actuated by the user to switch on and manually actuated by the
user to switch off, [0074]Hold-on switch requiring continuous pressure
from the user to maintain operation of the device and switching off when
released. This switch system provides the highest safety and energy
saving. [0075]Push button switch with timer in which the user activates
the device and the operation stops automatically after a pre-set time.
This mode of operation enables a controlled treatment durations and
reduces risks of over usage (irritation). The end of operation may be
indicated by a buzzer or the like. Optionally, the timer may be
controllable to operate for different periods, suitable for different
modes of treatment (for example, for different skin sites).
[0076]Optionally, operation may be made conditional on a predefined
minimum and/or maximum contact pressure between the device and the skin.
An example of a mechanism for cutting out operation in the case of excess
contact pressure with the skin is described below with reference to FIG.
2. [0077]In each of the above cases, an indicator light may be provided
to indicate when the device is operating. Optionally, the same indicator
light may be used to indicate low battery, for example, through flashing.

[0078]The deployment of the vibration generating mechanism and its
attachment to the other parts of the device are chosen relative to the
micro-protrusions in order to provide a desired form of vibrational
motion relative to the skin surface (e.g., orbital motion on the skin,
motion perpendicular to the skin, a back and fro motion on the skin, or
any combination of these motions). Thus, for example, in the case
illustrated here, axis 118 is substantially parallel to the surface of
substrate 104, resulting in vibratory motion having a first component
parallel to the skin surface and a second (non-zero) component
perpendicular to the skin surface. Alternatively, axis 118 may be
deployed perpendicular to the surface of substrate 104, resulting in a
rotating force vector in a plane of the substrate and a corresponding
orbital motion of skin interface element 102. A preferred non-limiting
range of frequencies for the vibration generating mechanism is between 50
Hz and 200 Hz, and most preferably, in the range of 140 Hz±25 Hz.

[0079]The application times for the dermabrasion treatment are preferably
less than 1 minute, and most preferably in the range of 10-35 seconds.
The following experimental data resulted from tests performed to evaluate
risks of irritation through the operation of the dermabrasion aspect of
the present invention, and show the action of the device to be
non-irritating as follows.

[0080]Experimental Procedure: The device was used to abrade small areas of
skin, app. 1 square cm in size on a daily basis for a period of 26 days.
3 sites were chosen on each arm, in the volar aspect, and one site on
each temple. Every site was abraded daily for a predetermined duration as
follows:

[0081]On each hand, one site was abraded for 5 seconds, one for 10 seconds
and one for 30 seconds. On the right temple, the site was abraded for 5
seconds and on the left temple for 10 seconds.

[0082]The contact force applied was approximately 3N. The vibrating motion
was mostly radial, i.e., generally parallel to the skin plane. The
application included circular motion as well.

[0083]Local irritation was assessed daily before abrasion using the Draize
score (Draize J H. "Dermal and eye toxicity tests" Principles and
procedures for evaluating the toxicity of household substances.
Washington, D.C.: National Academy of Sciences, 1997:31-2), as detailed
below.

[0086]Illumination system 109 may be any illumination system generating
light of wavelength(s) and intensity suitable for implementing the
desired type of phototherapy. By way of non-limiting example, the device
of the present invention is illustrated herein in the context of a
hand-held battery-powered device suitable for performing various types of
photomodulation. In this case, one or more light emitting diode (LED) of
suitable wavelength is preferably used. Other types of phototherapy,
including high intensity light application, may also be implemented
according to the teachings of the present invention, typically using a
device directly connected to an external electrical power source of
suitable rating. In each case, illumination system 109 is preferably
implemented with a built-in electronic control unit for controlling
current supply, power, and the operational duty cycle to implement the
desired phototherapy.

[0087]As mentioned, the type of light source and operational parameters
are chosen according to the specific field of implementation. For
example, current scientific literature suggests that light in the blue
spectrum (˜410 nm) is specifically effective for treating acne
(with or without the combination of photodynamic therapy), while the
yellow spectrum (590 nm) is specifically good for skin rejuvenation.
Light in the red and near infrared (NIR) spectrum (670-880 nm) is
particularly useful for inducing wound and tissue repair.

[0088]The mechanical abrasion caused by the vibration of the mechanical
skin interface (microprojections) is effective in certain cases to
enhance or augment the delivery of light energy into the skin, either by
allowing it to be delivered more deeply into the tissue, or provide
higher energy levels to the same tissue depth (or a combination of the
two effects).

[0089]Various applications of the invention combine the device with a
specific active composition (cream, gel, solution or the like). For
example, the device may be used as a cosmetic or dermatologic
pre-treatment, prior to application of an active composition, as a
cosmetic or dermatologic post treatment after the cream, paste or
solution were applied on treated site, or concurrently during application
of a cosmetic or dermatologic treatment.

[0090]In the schematic illustration of FIG. 1, illumination system 109 is
shown supported on an external surface of housing 110. Such a location is
possible in a practical implementation, either illuminating the region of
skin subject to dermabrasion from the side or alternatively illuminating
a region adjacent to the region currently undergoing dermabrasion so that
the phototherapy and dermabrasion occur sequentially as the device is
moved across the skin. An alternative implementation for simultaneous
administration of the two processes will be described below with
reference to FIGS. 5-8.

[0091]A further feature of certain preferred embodiments of the present
invention is illustrated schematically in FIG. 2. FIG. 2 shows a device,
generally designated 100', which is equivalent to device 100 of FIG. 1
except that it features an additional pressure-limiting switch
arrangement 124. Pressure-limiting switch arrangement 124 is responsive
to contact pressure of skin interface element 102 above a given limit to
interrupt operation of the vibration generating mechanism 108. This
ensures that contact pressure exerted by the hand of the user does not
reach sufficient levels to cause excessive penetration depth, or to lodge
protrusions 106 firmly into the tissue, an effect which might lead to
excessive damping of vibrations and consequent disruption to the efficacy
of the abrasion treatment. This feature is particularly important for
medical application (e.g., treatment to increase porosity of the skin to
enhance absorption of medication) where relatively longer protrusions may
be used and regulation of penetration depth therefore becomes more
important.

[0092]Structurally, pressure-limiting switch arrangement 124 is shown here
implemented as a circuit breaker included in the power supply circuit for
vibration generating mechanism 108. The resilient mounting of skin
interface element 102 allows for retraction of the skin interface element
as a function of contact pressure. By leaving an appropriately chosen gap
between the rear end of a shaft 126 of skin interface element 102 and the
circuit breaker, a desired threshold of contact pressure can be defined
for the cut-out function. Optionally, pressure-limiting switch
arrangement 124 may be configured to operate an alarm or buzzer (not
shown) if the contact pressure exceeds the defined limit. For most
applications, preferred contact force is in the range of 1-5 N, and most
preferably around 3 N. The cut-out function can thus advantageously be
configured to cut out operation of the device when a threshold chosen in
the range of about 3-6 N is exceeded.

[0093]Turning now to FIGS. 5-8, these illustrate one non-limiting
practical implementation of a device 200 constructed and operative
according to the teachings of the present invention. Device 200 is
essentially similar to device 100 illustrated schematically in FIG. 1,
with equivalent elements labeled similarly. However, the implementation
shown here illustrates a number of additional preferred features which
were either omitted or simplified for clarity in the schematic
representation of FIG. 1. These features will now be addressed.

[0094]Most notably, illumination system 109 is here implemented as a
hidden illumination system located within housing 110, as best seen in
FIG. 8. In order to enable delivery of the light generated by
illumination system 109 to the skin at or near skin interface element
102, at least part of substrate 104 and/or of a support structure 128
around the substrate is formed from a material substantially transparent
to light of the wavelengths generated. In the preferred example
illustrated here, a major part and typically the entirety of support
structure 128 is formed from medical/optical grade transparent polymer by
common technologies such as injection molding. An example of a polymer
material with suitable properties is polycarbonate which provides an
excellent combination of biocompatibility and optical performance.
According to a particularly preferred optional feature of the present
invention, for cases in which substrate 104 is opaque to the wavelengths
of illumination used, the transparent material is formed as a lens
configured to guide the light around the substrate and towards part of
the surface of the skin which would otherwise be obscured by the
substrate.

[0095]According to an additional, or alternative, approach, transmission
of light may be effected at least in part via openings formed through the
substrate. In some cases, an opening may be associated with each
projection, such as in the case of microprojections which are hollow or
otherwise formed with a through-channel.

[0096]In certain preferred embodiments such as illustrated here, skin
interface element 102 is implemented as part of a replaceable, disposable
sub-unit 130. This facilitates proper hygiene, enabling all parts of the
device coming in contact with the treated area of skin to be new and
clean for each use while avoiding unnecessary costs of replacing other
parts of the device.

[0097]Housing 110 and other parts of the devices of the present invention
which do not need to be transparent are preferably formed from common
thermoplastic polymers suitable for injection molding, such as for
example ABS (Acrylonitrile Butadiene Styrene).

[0098]Device 200 is also distinguished from device 100 described above in
that motor 114 is here deployed to rotate eccentric weight 116 about an
axis 118 substantially perpendicular to the plane of substrate 104, as
best seen in FIG. 8. As a result, the vibratory motion generated by the
device is primarily orbital motion in the plane of skin contact.

[0099]In all other respects, the structure and operation of device 100
will be fully understood by analogy to the structure and operation of
device 100 as described above.

[0100]Finally, it should be noted that the present invention may be used
to advantage in a wide range of cosmetic and medical application. By way
of non-limiting examples, various application procedures could be
employed in combining the device with a specific active (cream, gel,
solution or the like). For example: cosmetic or dermatologic
pre-treatment (skin treatment prior to applying the active composition),
cosmetic or dermatologic post treatment (using the device after the
cream, paste or solution were applied on treated site), and cosmetic or
dermatologic treatment: cream and projections applied concurrently. It
should be noted that particularly preferred implementations of the
present invention relate to general purpose devices which may be used
with various different treatment compositions, and wherein the device
itself typically does not store or apply the composition.

[0103]Turning now to an additional feature of the present invention, the
invention also provides an arrangement of projections which have
antibacterial coatings to inhibit or reduce microbiological organism
build up on and around the projections. This feature may be used to
advantage with the dermabrasion and phototherapy devices of the present
invention, but is also believed to be of patentable significance in a
wide range of other applications of micro-projections or microneedles in
the fields of abrasion, drug delivery, sampling and any other
skin-interface application performed with micro-protrusions, particularly
although not exclusively for applications in which the skin interface is
either re-used or used for an extended period.

[0104]The term "anti bacterial" is used herein in the description and
claims in a broad sense, to encompass any and all compounds, coatings or
surface treatments effective to reduce the effects of microbiological
contamination of a device, including, but not limited to, bacteria and
other microorganisms (such as fungi). The antibacterial coating may kill
bacteria, inhibit or reduce bacterial growth, and/or may reduce adherence
of bacteria to surfaces of the device. Additional benefits of such
materials and processes include the reduction or elimination of odors.

[0105]The anti-bacterial coating is preferably applied as a part of the
manufacturing process of the skin-interface element. The coating is
preferably chosen to be biocompatible, inexpensive and simple to
manufacture. The anti-bacterial coating may be produced from materials
such as: TITANIA (TiO2) and its derivatives, which are applied externally
and later radiated with UV light (provided preferably in a separate
lighting device). Titania coating is performed by well known techniques
(e.g., sputtering, Chemical Vapor Deposition--CVD, MOCVD, deep coating
etc.).

[0106]Additionally or alternatively, various metal ions could be used (or
added to form combinations) such as Ag+, Zn2+, Co2+, Al3+ and Hg2+, and
Cu3+. These materials have been shown to limit or inhibit bacterial
growth. Again, they could be applied using techniques such as sputtering,
deep coating, screen printing, painting, CVD, electroplating and other
known techniques.

[0107]Other examples of coatings for imparting anti bacterial properties
are a silver (and its derivatives) coating and BAK (Benzalkonium (BAK)
chloride) coating. These materials do not require radiation for
activation, and are know to exert anti bacterial properties. Additional
materials include known chemical-based anti microbial agents
(antibiotics).

[0108]The thickness of the anti-bacterial active layer is chosen according
to the properties of the coating material used and the intended
application, and lies in the range from a few nanometers up to hundreds
of micrometers.

[0109]Optionally, the coating may also include a "replacement indicator"
to indicate wearing out of a device or otherwise a need for a
replacement. This indicator is preferably implemented as an internal
paint layer which becomes revealed dependent on use or wearing (in a
similar manner to shaving blade indicators). Such internal paint layers
become noticeable shortly after mechanical wear reaches a predefined
stage, thereby indicating that the skin interface element should be
replaced.

[0110]It will be appreciated that the above descriptions are intended only
to serve as examples, and that many other embodiments are possible within
the scope of the present invention as defined in the appended claims.